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G4WYW > CW_ALD 29.07.05 17:23l 61 Lines 2599 Bytes #999 (0) @ WW
BID : FC9532G4WYW
Read: GUEST
Subj: Re: Aldis lamps..
Path: DB0FHN<DB0CL<DB0PDF<DB0SM<PI8DAZ<PI8CDR<ON0BEL<ON0AR<GB7FCR
Sent: 050729/1028Z @:GB7FCR.#16.GBR.EU #:59970 [Blackpool] FBB-7.03a $:FC9532G4
From: G4WYW@GB7FCR.#16.GBR.EU
To : CW/ALD@WW
G4WYW wrote:-
> For those interested, an Aldis Lamp works by switching a high power bulb
> on (150+ watts) where it remains illuminated, then operating a fast
> shutter mechanism that opens and closes the shutter rapidly. The
> "shutter"
> is like a circular section of "Venetian Blind" that "blinks" at the press
> of the trigger. This method ensures that the light (bulb) is always at
> full brightness and lengthens the life of the bulb filament which would
> probably soon burn out if it were relied upon for it to be switched
> on/off
> quickly.
> A highly polished silver concave mirror behind the bulb, concentrates the
> light to a narrow but highly intense beam of light that penetrates and
> can be seen even in bright daylight...
I have, since sending the above, read other descriptions of the 'blinking'
mechanism being a blackened tube that rapidly slides up and down the bulb
to either obscure or reveal the light. This is exactly how mine works and
I failed in my attempt to describe it accurately in my original sending!
I have just found my lamp which was in the dark recesses of a cupboard and
it is, in fact, made by Francis Searchlamps of Bolton, Lancashire,
England.
It is typical of all the "Aldis" lamps that I have seen on the bridge of
Merchant ships that I have been aboard and has the two triggers, one to
switch on the bulb, the other to move the 'blinking tube' surrounding the
bulb. It has a 'sighting' tube on top of the main housing and it also has
three studs to mount a metal circular blanking plate (to protect the glass
when not in use or to diffuse the light through the narrow gap?) but could
equally be used to attach the various different coloured glasses as Bryan
VK6HT described.
This black metal plate has the makers name embossed together with this:
M.O.T. S/100
The entire lamp and power cable fit into a custom box measuring roughly
12.5" x 10.5" x 8" with a hinged lid and single fold down clasp to keep
it shut and a leather carrying handle.
Here is the Oxford Dictionary definition of "Aldis":-
Aldis /lds/ n. E20. [A. C. W. Aldis (1878-1953), Brit. inventor.] In full
Aldis lamp. (Proprietary name for) a hand lamp for signalling in Morse
code.
---------------------------------------------------------
Excerpted from Oxford Talking Dictionary
Copyright © 1998 The Learning Company, Inc. All Rights Reserved.
73 - Mel, G4WYW @ GB7FCR.#16.GBR.EU
Message timed: 11:18 UTC on 29 Jul 05
Message sent using Winpack 6.80 (R)
Written by Roger Barker G4IDE.SK 9/9/04 R.I.P.
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